1. Field of the Invention
The present invention relates generally to an apparatus for suppressing noise which radiates from the ignition system of an internal combustion engine, and more particularly relates to an apparatus for suppressing noise which generates from the distributor located in the ignition system.
The igniter through which an electric current has to be passed quickly in order to discharge a spark, radiates the noise which accompanies the occurrence of the spark discharge. It is well known that the noise disturbs radio broadcasting service, television broadcasting service and other kinds of radio communication systems and, as a result, the noise deteriorates the signal-to-noise ratio of each of the above-mentioned services and systems. Further, it is very important to know that the noise may also cause operational errors in electronic control circuits, mounted in vehicles, such as E.F.I. (electronic controlled fuel injection system), E.S.C. (electronic controlled skid control system) or E.A.T. (electronic controlled automatic transmission system), and, as a result, traffic safety may be threatened. On the other hand, it has become increasingly important, due to the emphasis on clean exhaust gas for an electric current to be strong and to be intermitted very quickly in order to pass quickly and thereby generate a strong spark discharge. Such a strong spark discharge is accompanied by an extremely loud noise causing the previously mentioned disturbances and operational errors.
2. Description of the Prior Art
For the purpose of suppressing the noise, various kinds of apparatuses or devices have been proposed. Japanese Patent publication No. 48-12012 provides an example of the prior art. In it, the spark gap, between the electrodes of the distributor rotor and the stationary terminal in the distributor is selected to be between 1.524 mm and 6.35 mm, which is wider than the spark gap used in the typical distributor. A second prior art example is Japanese Patent publication No. 51-38853. In it, an electrically high resistive layer is formed on each of the surfaces of the electrodes of the distributor rotor and/or the stationary terminals. A third prior art example is Japanese Patent publication No. 52-15736. In it, an electrically resistive member is inserted in the spark gap formed between the distributor rotor and the stationary terminal, and the spark discharge occurs between the distributor rotor and the stationary terminal, through said electrically resistive member. A fourth prior art example is Japanese Patent publication No. 52-15737. In it, a dielectric member is inserted in the spark gap formed between the distributor rotor and the stationary terminal, and the spark discharge occurs between the distributor rotor and the stationary terminal by way of the surface of said dielectric member.
Thus, a distributor which incorporates either one of the above-mentioned prior art examples can exhibit remarkable suppression of noise when compared to the conventional distributor which contains no apparatus for suppressing the noise.